Continued from page 1
If
DNS server is unable to resolve
query, it in turns queries other DNS servers, using a process known as recursion. DNS servers make use of root hints to assist in locating DNS servers, which are able to provide
required result. In this way, DNS queries are minimised and
Internet is able to operate quickly and effectively.
A typical query may run as follows:
Client contacts Nameserver A looking for www.discountdomainsuk.com.
Nameserver A checks its cache, but can’t answer, so it queries a server authoritive for
Internet root.
The root server responds with a referral to a server authoritive for
.com domains. NameserverA queries
the .com server and gets referred to
server authoritive for www.discountdomainsuk.com.
Nameserver A queries this server and gets
IP address for www.discountdomainsuk.com.
Nameserver A replies to
client with
IP address.
Queries can return answers that are authoritive, positive, negative or referral in nature. In
event of a negative answer, another DNS server is queried.
